Saddle spinal block with low-dose intrathecal morphine for pain after penile inversion vaginoplasty

The Addition of a Saddle Block With Intrathecal Morphine for Analgesia in Transgender Patients Undergoing Penile Inversion Vaginoplasty: A Randomized Double-blind Placebo-controlled Trial

Not applicable Interventional Women's College Hospital · NCT06556121

This trial tests whether adding a motor-sparing saddle spinal block with low-dose intrathecal morphine to usual pain care reduces postoperative pain after penile inversion vaginoplasty for transgender women.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years to 70 Years
SexMale
SponsorWomen's College Hospital Academic / other
Locations1 site (Toronto, Ontario)
Trial IDNCT06556121 on ClinicalTrials.gov

What this trial studies

This is a randomized, placebo-controlled interventional trial at Women's College Hospital comparing the addition of a motor-sparing saddle block with low-dose (100 mcg) intrathecal morphine to standard multimodal analgesia and pudendal nerve block for penile inversion vaginoplasty. The saddle block uses ultra-low dose hyperbaric spinal local anesthetic to target sacral pain fibers while limiting motor effects and rostral opioid spread. Participants are adult patients (ages 18–70) with ASA I–III status undergoing primary penile inversion vaginoplasty. Outcomes include postoperative analgesia, opioid consumption, and opioid-related adverse effects measured in the perioperative period.

Who should consider this trial

Good fit: Ideal candidates are transgender women aged 18–70 undergoing primary penile inversion vaginoplasty who are ASA I–III, can read/speak English, are not chronic high-dose opioid users, and have no contraindication to spinal or local anesthetic techniques.

Not a fit: Patients on high-dose opioids (over ~30 mg oxycodone-equivalent per day), those with contraindications to spinal or local anesthetics, and those undergoing revision or vulvaplasty are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, the intervention could provide stronger and longer-lasting perineal pain relief after surgery while reducing systemic opioid needs and related side effects.

How similar studies have performed: Intrathecal opioids and motor-sparing saddle blocks have shown effective analgesia for abdominopelvic and perineal procedures in prior work, but the specific use of low-dose intrathecal morphine for penile inversion vaginoplasty is largely novel and previously supported mainly by anecdotal experience.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* ASA I-III patients
* Ages 18-70 years
* Penile Inversion Vaginoplasty

Exclusion Criteria:

* Local infection
* History of use of over 30mg oxycodone or equivalent per day.
* Contraindication to a component of multi-modal analgesia
* Complications or adverse events unrelated to the local anesthetic that precludes evaluation of the primary and secondary outcome measures.
* Unable to speak or read English.
* Revision and Vulvaplasty surgeries

Where this trial is running

Toronto, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Pain, PostoperativeSaddle blocktransitionpudendal nerve blockgender confirmation surgerypenile inversion Vaginoplasty
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.